Analysis of flicker mitigation in a utility distribution network

A regional utility company in Slovenia reported excessive flicker levels that are caused mainly by a 4 MVA arc furnace installed in the area. This paper evaluates two possible solutions for flicker mitigation: increasing the short-circuit power at the point of common coupling; and installation of a D-StatCom system. Based on the field measurements, a detailed network model was constructed in the PSCAD/EMTDC program to verify the proposed solutions. The arc furnace and an IEC flicker-meter for flicker level evaluations were also modeled. A comprising solution to flicker mitigation was analyzed. The utility could reduce the flicker level from 4 to around 1.9 by replacing its HV/MV transformer. Further reduction of flicker (the permissible level is set to 1) should be done by the customer with the application of a D-StatCom compensation system. The structure and control of the device are proposed in this paper.